[LARTC] Qos with 2 internet connections problems

[Francisco Pereira]

Anthony Letchet wrote:
> Hi all, ive got 2 internet connections set up via the nano howto (which
> are working great)  and we are running NAT.
> Was looking in to qos mainly to stop large http downloads/ftp downloads
> from hogging the line so that browsing for other users doesnt slow to a
> crawl, but if the line is free and no one is doing anything then for it
> to use the available bandwith. The wondershaper sounded exactly what i
> wanted, i obviously had to customize this slightly to get my other
> connection to be shaped as well.
> my connections are 2 adsl connections running at 512kbit:256kbit, i
> compiled the kernel with all the tos + iptables stuff (eventually) so
> that the script ran without any errors, once it had i did a download on
> each pipe and then tried to ping jolt.co.uk and google.co.uk, jolt.co.uk
> normally is about 15ms, so i was hoping that it would maybe be 200ms
> with my new shaping, but it was coming at about 900ms+ google was the
> same. Browsing other website was also to a crawl (what i was trying to
> avoid) but i did notice that when traffic came from our mail server
> through my gateway it was only receiving at about 25k/sec instead of
> 2mb/sec etc as its on a 100mbit switch. So something was obviously
> shaping, so i suppose i will now need to look in to specifying some of
> the hosts which are local to me but are on the outside interfaces and
> for them not to be shaped.. But still no better off :(
> 
> Ive been reading various howtos like the adsl bandwith management howto,
> but these havnt been updated in about 3 years and they mention various
> techniques which were being tried back then to help with these kind of
> situations, so what i really want is a howto which shows all these new
> features? or is this adsl bandwith management still current ? :)
> 

I would recommend reading the masters thesis of Jesper Dangaard Brouer 
at http://www.adsl-optimizer.dk/thesis/
Altough he didnt release software yet (there is some code & patches in 
the pdf file) which could lead to the best solution, you could estimate 
the adsl overhead with real knowledge, and not like it says in some 
scripts (put x kbit less than the link bandwith, or 5% less,...)

> my network diagram
> 
> Lan machines -> Linux Router -> Alcatel Router -> ADSL
> Lan Machine -> linux router -> alcatel router2 -> ADSL
> 
> Alcatel router -> Linux router
> Alcatel router -> mail server etc
> 
> 
> 
> 
> my modified wondershaper script is below: if anyone could point out some
> errors and or maybe point me to somewhere where i could learn how to do
> what i want better please let me know.
> 
> 
> 
> #!/bin/bash -x
> # Wonder Shaper
> # please read the README before filling out these values
> #
> # Set the following values to somewhat less than your actual download
> # and uplink speed. In kilobits. Also set the device that is to be shaped.
> 
> DOWNLINK=512
> UPLINK=256
Too much. Because ATM overhead (5/53), 463/231 is the actual maximum 
bandwith.
And you have yet to consider the per packet overhead. Read the thesis I 
mentioned.

> DEV=eth1
> DEV2=eth2
> 
> DOWNLINKlan=512
> UPLINKlan=256
> DEVlan=eth1
> 
Did you use the DEVlan variable?
eth1 is LAN and external at the same time?

Have you looked at http://routeskeeper.sourceforge.net/
or http://selab.edu.ms/twiki/bin/view/Networking/RoutesKeeperProject

Regards,
Francisco.